• MESO: Mesoscale Discussion 0243

    From COD Weather Processor@1:2320/105 to wx-storm@lists.illinois.edu on Wed Mar 19 16:22:20 2025
    ACUS11 KWNS 191622
    SWOMCD
    SPC MCD 191621=20
    ILZ000-IAZ000-MOZ000-191845-

    Mesoscale Discussion 0243
    NWS Storm Prediction Center Norman OK
    1121 AM CDT Wed Mar 19 2025

    Areas affected...central Illinois

    Concerning...Severe potential...Watch possible=20

    Valid 191621Z - 191845Z

    Probability of Watch Issuance...60 percent

    SUMMARY...A gradual intensification of thunderstorm activity is
    likely across parts of southeastern Iowa into west central into
    central Illinois through 1-3 PM CDT. This may include increasing
    potential for a couple of tornadoes, severe hail and locally strong
    surface gusts. Trends are being monitored for the possibility of a
    watch, which appears more probable across parts of central/eastern
    Illinois later this afternoon.

    DISCUSSION...Scattered, modest convective development has been
    occurring to the east-northeast of a deep, occluding cyclone now
    centered north of Kansas City. This has been focused along a
    dryline, which may continue to become better defined into early
    afternoon, as the Rapid Refresh suggests that the trailing cold
    front may not quite overtake it. The leading edge of the primary
    cooling at mid-levels is contributing to steepening lapse rates
    along the dryline and, with a gradual moistening (surface dew points
    increasing through the lower 50s) of the boundary-layer ahead of it, appreciable further destabilization is expected. It appears that
    this may include mixed-layer CAPE increasing to 500-1000 j/kg in a
    corridor from near the triple point across the southeastern Iowa
    vicinity into central Illinois.

    As this occurs, initially scattered, low-topped thunderstorm
    development is likely to undergo a gradual intensification, beneath
    an intense south-southwesterly mid/upper jet. Low-level hodographs
    remain rather modest to weak, and Rapid Refresh forecast soundings
    suggest that this may not change much until later this afternoon
    across parts of east central Illinois (roughly near/east of the
    Bloomington and Decatur vicinities). However, it is possible that
    ambient vertical vorticity and steepening low-level lapse rates
    along the dryline, near the triple point, may support potential for
    at least a couple of generally brief/weak tornadoes, in addition to
    severe hail and locally strong surface gusts.

    ..Kerr/Leitman.. 03/19/2025

    ...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8IxHmbjZE0O_yU_UAS8Is7BncIu8ktbs2aOEekoGBJ-Njx96q7UKe682wNKCympF9zVnczrzp= prN1VYLy86a1-sQydY$ for graphic product...

    ATTN...WFO...LOT...ILX...LSX...DVN...

    LAT...LON 41469066 41088906 38938848 38998954 39438987 39639122
    40889185 41469066=20


    =3D =3D =3D
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